Drawing quirks in Level 1-1 example

I see a drawing oddity in the Level 1-1 Example, when head butting a question mark block. the bottom is visible during the animation and the top line of the block is missing after the animation and until the screen is redraw by scrolling the level.

I've not checked any old SDK versions to see when this started happening.

animated gif capture:


stills of the drawing quirks: